1. Field of the Art
The present application relates to clinical testing systems, and in particular to test systems in which sample containers are processed using pipettors or other devices that may tend to lift the sample containers. Other uses will, however, be readily apparent from the present disclosure.
2. Description of Related Art
Medical sample processing equipment often includes pipettors, aspirators, and other devices to remove substances from and add substances to containers. For example, it is known to aliquot specimens from biological sample containers using a pipette, and to aspirate wash buffers or other fluids from containers during processing. it is also known to add fluid to containers using pipettes, nozzles, and the like. Typical containers vary in size and shape. Typical containers can hold blood, urine, liquid-based cytology (LBC) samples containing tissue or other matter, reagents, buffers, control samples, calibration samples, and so on.
In many instances pipetting, aspirating and other fluid withdrawal processes are simple and straightforward operations with little complication. This is particularly true where the container is firmly held during the process, and there is little likelihood that the pipettor or aspirator will contact or move the container. However, where large numbers of containers are being processed, it may be cumbersome to affix each container to a rack or other surface or structure (using threads or cam-locks, for example) to hold them down during processing. Thus, it is often preferred to hold containers by slipping them with little friction into form-fitting wells.
Some containers, however, may not be held firmly during a pipetting or aspirating process, making them more susceptible to movement due to contact by the fluid removal device. Such contact may lead to spills or unwanted movement. In addition, some containers may include a foam, foil and/or elastic cover through which the pipettor or aspirator passes to access the container's contents. Examples of such containers are found in U.S. Pat. Nos. 6,752,965; 6,030,582; 5,514,339; 5,370,252; 5,297,599; 4,243,150 and 3,088,615, which are incorporated herein by reference. Still other containers are shown and described in European Patent Nos. 0 115 480 and 0 081 976; and International Application No. WO 00/69389. Some of these seals are intended to re-close, at least to some degree, after the pipette or aspirator are removed from the container to help prevent evaporation, cross-contamination, or inadvertent loss of the contents. As such, the cover may exert a restoring force against the pipettor or aspirator, creating friction between the two during insertion or removal. Even foil seals, which tend to deform plastically without generating a significant restoring force, can still catch on or grip a pipette or aspirator as it is removed.
Contact between a cover and a pipette or aspirator can generate a significant force that can move the container. For example, contact between a cover and a pipette may lift a container partly or entirely out of a container rack or tray holding the container. In view of this, some form of retainer may be used to hold the container down as the pipette or aspirator is being removed. In manual processes, the retainer typically is a person's hand. In automated processes, a typical retainer may be a flat panel located over a rack of containers. The panel may have notches or holes through which the pipettes or aspirators access the containers, but these holes or notches are small enough or shaped to prevent the container from rising above a predetermined height as the pipette or aspirator is removed.
Although prior retainers may be effective in some circumstances, it has been determined that there is a need for alternative retaining systems to hold sample containers as devices such as pipettes, aspirators, and the like are being withdrawn form the container. The following description provides exemplary embodiments of alternative retaining systems.